Supplier of Diesel Fuel Tax Return

General Information

Per Regulation 1420, Supplier, all licensed fuel suppliers are required to report tax on (undyed) diesel fuel. The Diesel Fuel Tax is imposed on the following activities:

  • Removal of diesel fuel from a refinery or terminal rack;
  • Importation of diesel fuel into California by means outside the bulk transfer/terminal system;
  • Removal or sale of diesel fuel to an unlicensed person unless there was a prior taxable removal, entry, or sale; and
  • Removal or sale of blended diesel fuel outside the bulk transfer/terminal system.

All transactions involving these activities are subject to tax unless the transaction meets one of the exemptions allowed in the Diesel Fuel Tax Law. Dyed diesel fuel is not subject to tax unless it is used to operate a motor vehicle on a highway; however, it is subject to all of the reporting requirements applicable to undyed diesel fuel.

Note: Every July 1, the diesel fuel tax rate is adjusted based on changes in the California Consumer Price Index. The California Department of Tax and Fee Administration (CDTFA) generally announce the adjusted rate by the preceding May 1. Due to this annual rate adjustment, you may have transactions at several different tax rates. The diesel fuel tax rate is located on the Special Taxes and Fees Tax Rates webpage, under Diesel Fuel Tax.

Filing Requirements

Every licensed diesel fuel supplier is required to file the Supplier of Diesel Fuel Tax Return and schedules, reporting all diesel fuel activities – removed, entered, or sold in California during the reporting period, on or before the last day of the calendar month, following the reporting period. These activities include importing and exporting above and below the terminal rack, blending, and refinery or terminal rack removals of diesel fuel in this state. You are also required to report jet fuel and kerosene - imported, exported, or sold during the reporting period. (Regulation 1420)

A return must be filed for each reporting period even if you do not have any activity to report. Remittance for the amount due must be submitted by the due date of the return. A copy of the return and schedules must be retained on the licensed premises for verification by CDTFA auditors.

Penalty and Interest

The penalty for filing a late return and/or late payment is ten percent of the amount due for the period. Interest also applies to late payments for each month or fraction of a month that the payment is late.

Failure to file a return may result in revocation of your Diesel Supplier license and a $50 reinstatement fee (Revenue and Taxation Code 7510)

Accountability

You must report all transactions that are required on this tax return and schedules. CDTFA will be comparing your total rack removals, as reported by terminals, against removals reported by you. Your imports of products will be compared to exports reported to CDTFA by other states. Failure to report fully may result in CDTFA contacting you.

Schedule Preparation

A CDTFA-810-FTG, Receipt Schedule and a CDTFA-810-FTF, Disbursement Schedule, must be submitted with every Supplier of Diesel Fuel Tax Return, to support applicable activities during the reporting period.

For detailed information regarding preparation of the schedules, please refer to CDTFA-810-FTE, Instructions for Preparing Motor Fuels Schedules, Supplier Schedules section.

List of codes used in schedule preparation can be located on our website, under Guidelines of the Motor Fuels Online Filing webpage.

Tax Computation Worksheet Preparation

The Tax Computation Worksheet is provided to assist you in calculating the tax due and completing your return. This worksheet should be kept with your records. When completing the schedules, please remember that tax is due on total gallons sold, including partial gallons; therefore, round up or down to the nearest whole gallon to avoid reporting errors.

File Attachment

To submit your CDTFA-501-DD-E, Supplier of Diesel Fuel Tax Return, click the Add button to upload the file attachment.

On the Select a file to attach pop-up window:

  1. Click the Type drop-down menu and select the appropriate file type. Available options to select from:
    • EDI Attachment (Electronic Data Interchange)
    • Motor Fuels Flat File (FLT)
  2. Enter a description of the file in the Description field (for example: Account 123-456789, Period Jan. 2023).
  3. Click the Choose File button and follow the prompts to select and upload the file.
  4. Once you have completed all required information, click the Save button.

Click the Next button to proceed to the next screen.

For instructions on file preparation, including file type and formatting requirements, template Excel workbooks for creating Flat (FLT) files, sample files, and other useful information related to motor fuels online filing, please visit our website at www.cdtfa.ca.gov.

Note: If filing an amended return, only report transactions that occurred within the reporting period.

Review Totals

Do you agree with the tax due or refund calculated from the schedules?

The reported tax due or refund claimed from the file attachment may be different than the calculated tax due or refund claimed from the schedules.

If you agree to use the tax due or refund calculated from the schedules, select Yes and click Next.

If the calculated tax or refund from the schedules is incorrect, do not proceed. You must first correct and resubmit the file attachment. Select the Previous button and follow the instructions to resubmit a corrected file attachment.

Excess Tax Collected

Did you collect more tax than what is due (excess tax)?

If you have collected more tax than what is due (excess tax) for this reporting period, select Yes and enter the amount of excess tax collected. (Revenue and Taxation Code 60521.5)

If you did not over collect for this reporting period, select No.

Excess tax collected can occur in the following situations:

  • When tax is computed on a transaction which is not subject to tax;
  • When tax is computed on an amount in excess of the amount subject to tax;
  • When tax is computed using a tax rate higher than the rate imposed by law; and
  • When mathematical or clerical errors result in an overstatement of the tax on a billing.

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